The integral abutment design of the taxiway bridge, currently under construction at the Piedmont Triad International Airport in Greensboro, NC, will provide the strength required to accommodate the extreme weight and width of large aircraft.
According to Mickie Elmore, director of development of the Piedmont Triad Airport Authority, the taxiway will be part of the airport’s development for the FedEx Mid-Atlantic Hub. Once complete, the new facility will be the company’s fifth major U.S. air cargo hub.
The hub will be a regional center serving primarily east coast destinations. Packages originating on the east coast for east coast delivery will be handled through the Piedmont Triad hub. Initially, the hub will be capable of sorting 24,000 packages per hour and will serve 20 to 25 aircraft each weekday. An agreement between FedEx and the airport authority calls for the hub to open no later than mid-2009.
According to Jeffrey Gagnon, construction manager for Baker and Associates, a division of Michael Baker Corporation of Pittsburgh, PA, grading the hub site (which has an estimated cost of $20.5 million) and constructing Bryan Blvd. (at a cost of $44.2 million) began in 2004. English Construction Company Inc. of Lynchburg, VA, began constructing the $10 million taxiway bridge in April 2005.
“The taxiway bridge will run over existing Bryan Blvd., connecting the airfield to the future Fed Ex buildings,” Gagnon said. “It will be constructed of concrete and steel — 174 ft. wide and 142 ft. long; wide enough to accommodate Group V aircraft.”
According to Elmore, there will be three phases of construction associated with the building of the taxiway:
• Phase 1, construction of the taxiway bridge. The $9.8- million contract was awarded to English Construction Company Inc. of Lynchburg, VA. Bridge design was done by Talbert and Bright Associates of Charlotte, NC.
• Phase 2, the grading of the taxiway that leads to the bridge. The $20.5-million contract was recently advertised and is expected to be awarded by the end of the year.
• Phase 3, the paving and finishing electrical work. The contract for this work will be let in late 2006 or early 2007. Early projections estimate the cost of this phase to be $5 million.
The integral abutment design of the bridge has created an atypical challenge for the contractor.
“The abutment design of the bridge, where the bridge deck and abutment are a fixed connection with no expansion joints, creates a frame system that will support the weight of an aircraft,” Gagnon explained.
Standard construction techniques are being used in the building of the bridge.
“Concrete for the wing walls is poured first and then for the abutments,” Gagnon said. “Fifty-eight, four-foot steel I-beam girders attach the bridge deck to the abutments. The final concrete pour will tie the bridge deck and girders into the abutments.”
Approximately 24,720 sq. ft. of concrete will be used for the deck slab and approximately 1.25 million lbs. of structural steel will be used for the taxiway bridge.
Earthwork and bridge construction will progress in tandem.
“Because the bridge is being built over an existing road, the excavation work under this contract was minimal,” Elmore said. “ In addition, the second phase contract will incorporate the majority of the earthwork.”
Approximately 8,000 cu. yds. of unclassified excavation and 122,000 cu. yds. of borrow excavation are required under this contract, Gagnon said.
Erosion control issues preceded site preparation.
According to Elmore, preparation for the building of the taxiway bridge involved meeting the requirements of the North Carolina Department of Natural Resources for erosion control. This included installing silt fences, temporary sediment basins and drainage to control erosion. Once this was done, site clearing began.
“Phase 1 of the taxiway project began in April of 2005 and is expected to be complete in the fall of 2006. There are between 20 to 25 employees at the job site daily,” Elmore said.
Gagnon said the bridge project, as well as the entire hub project, has been going well and is on schedule.
“Our biggest challenge [was from] complications due to weather,” he added. CEG